1. Field of the Invention
The present invention relates to a generating method and a generating system utilizing combustion exhaust gas to effectively use gas pressure and exhaust heat of combustion exhaust gas discharged from internal combustion engines.
2. Background of the Invention
Recently, internal combustion engines (engines) have increasingly installed supercharging devices such as turbochargers and supercharger to obtain large power output in case of necessity.
The turbocharger effectively utilizes exhaust gas pressure of exhaust gas that has been wasted in conventional naturally-aspirated engines. And the turbocharger is a supercharging device that provides rotational force to shafts by a force of combustion exhaust gas of the engine, thereby rotating a coaxial compressor to increase amount of intake air. Although 30% to 40% energy of fuel is wasted in the air as combustion exhaust gas in general engines, energy of this exhaust gas is utilized to increase power without increasing exhaust emission volume.
On the other hand, the supercharger is a mechanical charger that uses engine power itself whereas the turbocharger uses the exhaust turbine. In the supercharger, an engine and a compressor are linked with a belt and rotation drives the compressor to deliver the compressed air to the engine. Over the exhaust turbine, it has advantages including high responsiveness, low deterioration of fuel efficiency, and operability from the middle-rotation region. On the other hand, it has disadvantages including more loss in the high rotation region because the compressor is driven by the engine power and lower compression pressure than that of the turbocharger.
In the turbocharger, the exhaust gas emitted from the engine is introduced into a turbine case to cause the turbine to rotate at high speed and then the exhaust gas is emitted outside. The compressor coaxial with a turbine shaft is rotationally driven due to turbine rotation and the air inducted from the outside is compressed. The high-temperature air thus compressed is sent to an intercooler and cooled to increase air density. Subsequently the air is forced into an engine cylinder in a high density state and explosive burning with fuel produces high engine power output.
The engine power output increases in proportion to three factors “explosive force”, “emission volume”, and “engine rotational speed”. Therefore, the higher explosive pressure obtains the higher power output in comparison with the engines having the same emission volume and rotational speed. Although the explosive pressure is determined by various conditions, the higher boost pressure (pressure of the compressed air sent into the combustion chamber) increases the explosion pressure more. And even though the boost pressure is the same, the explosive pressure increases because the air volume (air density) increases as the intake-air temperature of the compressed air decreases.
Here in the turbine of the turbocharger, the intake air is compressed by rotating at extremely high speed of about 50000 rpm to 100000 rpm due to pressure of the combustion exhaust gas. And the temperature of the compressor adjacent to the turbine also becomes high because the turbine is exposed to the exhaust gas at high temperature appropriately 900° C. For this reason, the temperature of the compressed air compressed by the compressor becomes high as well.
The high-temperature compressed air is required to cool down before supplying the compressed air to the engine because density of the high-temperature air becomes low, and therefore an intercooler is used as a cooling device. By the air introduced from outside, the intercooler contactlessly cools down the compressed air erupting from the compressor of the turbocharger.
With respect to the invention relating turbochargers, invented are many devices disclosed for example in “A multicylinder-type gas engine provided with a turbocharger having generator motor” of Patent Document 1.
Patent Document 1: Japanese Unexamined Patent Publication No. JP-A-6-33780